I had the same problem with the Momentum over ear headphones I just couldn't get a good seal. I even bought the Momentum on ears to compare with the HD25's Alu and Amperiors but the Momentums couldn't compete with either in sound, construction or comfort.
To your question I've never owned the original HD25's and the Amperiors were the first iteration followed by the HD25 Alu for these headphones. But depending how you plan on using these and what your using to drive them I found the Amperiors to handle being plugged directly into my phone or iPod better than the HD25’s, where the HD25’s sounded better out of my desktop setup. The HD598’s with the bigger soundstage do to the open back design would probably make the biggest improvement in sound quality though.
I suggested the Amperior with regards to the pricing. From what I see other people to be saying, the Amperior is more of a side-grade, while the HD25 Aluminum is the upgrade. I mention this as of course, this is dependent on what you hear. In my own opinion, I do find the HD25 Alu to be better than both but I was actually hesitant at first due to its higher price as compared to the other two.
Referring to your original post, what did you mean by "calm, relaxed styles"? The HD598 aren't the heaviest in bass (neither is the K550, even if it's a close back) but I do recommend them over the K550. In fact, if you choose the K550 over the HD598, may I also suggest reading on the SoundMagic HP100 (as compared to the K550)?
Thank you very much for you replys guys..... :)
My sources are mostly portable players. Usually my nexus 7 or my 4th generation ipod touch. I dont have any amps (i dont like to be amp dependant, specially on the go....).
The momentums are really i very sad case because i really do love the looks and the sound. They are the best pair of headphones i ever owned for sure and i never had anything that matched their resolution. The problem is that already it home it is hard to get a good fit, but on the go its almost impossible..... to have a lifestyle headphone and not being able to use it on the street its not very smart.... thats why they are going unfortunatelly. If only sennheiser released bigger pads like v-moda, but unfortunatelly i dont see that coming anytime soon (and if they do, the original pads are already too expensive so imagine XL ones.... XD ).
By calm styles i meant artists, like james blake, metronomy, keane, coldplay, stuff like that..... the hd25's would be a better performer for the early artic monkeys, biffy clyro, and edm stuff i guess....
But wich one do you think is the better all rounder maricius? wich one is bassier and has more body (closer to the momentums), the hd598's or the k550's?
Would you guys consider any of these two headphones one step ahead of the over ear momentums? Matching or better resolution, sq, and refinement?
I briefly tried the hd598's a couple of weeks ago. i liked them but my impression was that they did not have such a strong body sound as the momentums, but to be honest its hard to test a a open headphone in a noisy store, and in christmas time its even worse. I plugged them to my ipod at the time so it also could be it....
Oracle, do you think the amperiors or the hd25 alu's are on par with the over ear momentums in terms of sound quality, resolution and refinement?
I think i am going for the hd598's as my first open headphones, my only doubt is, should i stick with my hd25's or should i swap them for a pair of amperior's since they are going to be my all rounder headphone after all (i could always keep the hd25's and the amperiors baut maybe thats a liiiiitlle too much..... XD )